Yes, his instinct of survival came into play. The movie didn't exactly point it out, but in several scenes he is shown in the background helping passengers into the lifeboats.

#1.) When Cal puts the money in 1st Officer Murdoch's pocket, look in the background. You can see Ismay go after a woman who was standing nearby, as if comtemplating weather or not to approach the boat, he grabs her arm and helps her to get in.

#2.) Also when 1st Officer Murdoch looks at Cal and Lovejoy and says "anyone else" you can see Ismay helping passengers get into the lifeboat.

Then after that comes the part where Ismay himself climbs into the lifeboat.