TALLAHASSEE (CBSMiami/NSF) - The volume on the fourth floor outside the House and Senate chambers is reaching a crescendo. Lobbyists are jockeying for positions in front of the chamber doors as lawmakers emerge for quick pow-wows. It’s all part of the last-minute frenzy as, in the words of powerful Sen. John Thrasher, “bills are dying.”

Priorities of House and Senate leaders — including pensions, school vouchers and medical marijuana — are all “trade bait” as the days wind down before the session’s scheduled finale on May 2.

Telemedicine, hospital “trauma drama” and a Central Florida expressway authority are on the “B-list” of issues that are part of the mix. And don’t forget the perennial sports stadium Hail Mary.

But overshadowing them all is a coveted and controversial piece of legislation already passed by the House and, as of this week, being pushed by Gov. Rick Scott as well as his likely opponent, former Gov. Charlie Crist. The measure, now stuck in the Senate, would allow undocumented immigrant students to pay much cheaper, in-state tuition rates. The proposal (SB 1400) also could prevent tuition increases for all students at universities and save money for parents paying into the state’s pre-paid tuition program.

“This session will not end peacefully if that bill does not get a vote on the Senate floor,” Sen. Tom Lee, a Brandon Republican who served as Senate president, predicted. “I don’t think anyone’s operating under any alternative illusion. So they can posture and dream in Technicolor all they want, but this issue will come up on the Senate floor or this session will melt down.”

Sen. Jack Latvala, the Clearwater Republican sponsoring the measure, said he expects the proposal to come up for a vote on the floor next week.

Thrasher, a veteran lawmaker and former lobbyist who also served as House speaker, said this year’s horse-trading is much like any other session. Thrasher’s late-in-the-game effort to separate an engineering school run jointly by Florida State University and Florida A&M University is still in play.

“It’s the usual dance that we usually get at this time of the year. There’s nothing unusual about that kind of stuff,” Thrasher, a St. Augustine Republican who is also chairman of Scott’s re-election campaign, said of the overall deal-making between the two chambers.

Unlike in previous years when lawmakers scrabbled over how to plug budget holes, this year’s $1 billion-plus surplus has rendered state spending talks tame.

And, publicly, House and Senate leaders are downplaying differences as coveted items are slipped in and out of conference spreadsheets, are tucked into budget fine print or quietly appear in the back of the budget bill, which will land on lawmakers’ desks on Tuesday.

“This time of year it’s pretty typical that one side’s going to hold back what the other side wants until they think they can get something from that other side that they want,” said lobbyist Jon Costello, who once worked as Scott’s legislative affairs director.

Lawmakers are engaged in “a lot of posturing,” Costello said, in preparation “for whatever grand bargain will close the session.”

Unresolved Senate priorities include a proposal (SB 1030) that would open the door for a type of marijuana that doesn’t get users high but could dramatically reduce life-threatening seizures in children with a rare form of epilepsy. Senate President Don Gaetz is backing the proposal, pushed in the House by his son, Rep. Matt Gaetz, R-Fort Walton Beach.

Other Senate items on the table include a plan dealing with the state’s natural springs and a proposal to create a multi-county expressway authority in Central Florida, home to incoming Senate President Andy Gardiner, R-Orlando.

“There’s no wheeling and dealing in the last couple of days,” Gardiner said wryly as he headed into negotiations with the House over transportation and economic development issues Wednesday morning.

A handful of Weatherford’s other priorities, apart from the in-state tuition for illegal immigrants, remain in limbo.

The speaker wants an expansion of the state’s de facto school-voucher system and an overhaul of the Florida Retirement System. Both items appeared in major amendments in the Senate Appropriations Committee on Tuesday, causing former president Lee to erupt. Lee stormed out of the committee room after casting a “hell no” vote on the pension plan.

The House is also pushing a health care “train” dealing with trauma centers, telemedicine and an expansion of nurse practitioners’ powers.

Lobbyist Brian Ballard predicted that Weatherford could walk away from some of his other issues if he wins on the immigrant tuition bill, which half of the speaker’s own GOP caucus rejected.

“I think if the speaker got that, my guess is the world would be a very smooth place,” Ballard said. “It sounds like he would be willing to let a lot of the Senate priorities go. People underestimate that Will Weatherford is a very strong guy and a very tough guy. He’s going to have some cards to play.”

Sen. Nancy Detert, R-Venice, was one of a handful of members who opposed the in-state tuition bill, which Senate budget chief Joe Negron, R-Stuart, refused to put on his committee’s agenda this week. Detert hinted at tension within a Senate GOP caucus fractured over the issue.

“You want to know what’s different this year? There’s always last minute wheeling and dealing. Generally it’s from the top down. This year, it’s intramural arm-breaking. It’s not coming from the Senate president. It’s not all about what the Senate president wants and we’re going to break your arm if he doesn’t get it. It’s more intramural boxing,” she said.

Whether an outwardly calm atmosphere remains during the final seven working days of the session will depend on “how much the leaders are going to dig in on their priorities,” Lee said.

Scott’s “veto pen is locked and loaded,” and Weatherford and Gaetz, who caved on doing away with greyhound racing this week, are in their final days as leaders of their chambers, Lee noted.

“It’s kind of the last chance for romance. So we’ve got to bring it in for a landing because when they roll out of here on May 3, their tenure as a presiding officer will essentially be over,” he said.

This report is by Dara Kam with The News Service of Florida.