Far as I can figure the only way Icebreaker can work is if the cloning vats that produce the specimens were being transported on the boat, and somehow got activated to provide the endless waves of specimens for the duration of the game.
In terms of why it would be on there when the DRF commandos are on there is a little harder to explain. If I were try and loosly tie them together I would say something like:
Upon containing the outbreak and capturing these Vats, the big wigs (whoever they are, government representatives most probably) decided they were more valuable intact than destroyed and ordered them to be transported overseas for further analysis.
Kevin himself would probably have been defeated and knocked out (rather than killed) and would be contained on the icebreaker as well, also for further analysis. While in mid transit Kevin's incredibly powerful body and rapid healing abilities would overcome the wounds he had sustained and any sedatives being used while transporting him and allow him to recover fully concious.
Without letting on to his captives he readied himself, and ensured his weaponry was still fully functional before ripping free of his bonds and ripping through any DRF troopers that were standing in his way. He would then procede to the hull and activate the machines to power the rebuilding of his beloved specimens and unleashing them on the rest of the crew.
As 1 of the few survivors of the local outbreak, its up to you to defeat every last one of them once and for all
Thats the only way i can figure it would work. Very very loose, and I cant be bothered to write it out properly... but thats the sort of line I would go down
