Broken Razor Blade?

Anyone notice that, at least currently on PS4, the Razor Blade is kinda sorta broken? If you're at half a red heart with a couple of soul hearts and have the Polaroid, when you use the Razor Blade once, it naturally triggers the Polaroid effect which gives you a temporary shield. Nothing wrong there. What IS wrong however, is that WHILE that temporary shield is up, you can spam the HELL out of the Razor Blade, not take damage, but still get a damage up for every single usage. I got up to 100 damage on mega Satan in exchange for 3 soul hearts, it was dumb XD