I see there is a lot of contention with this rule and I can understand why. Here is the way I see it:
Wording issues aside, the intent seems obvious in that Shrike can infiltrate with any squad he joins. So yes, infiltrating terminators could happen. HOWEVER:
I will say this, Shrike is currently under investigation for heresy. Terminators infiltrating isn't something that you could see happening fairly regularly. Fleeting infiltrating terminators is warp sorcery. Every time a terminator fleets an eldar player cuts himself. All fleeting terminators shall recieve the full measure of justice due them for their dabbling in mysterious powers. The Emperor's justice is the Emperor's mercy and their heresy shall not go unnoticed.
So, can you infiltrate terminators with Shrike: Yes.
Should you infiltrate terminators with Shrike: No.