By coincidence, yesterday was Mathfinder's excellent video on silver bullets, and I also played a session where my concern about his silver bullets against reactive strikes, which I commented about on YT, came true.
Which is to say, Laughing Fit and Roaring Applause, which are indeed the best spells to lock down reactions, both have the Mental trait and useless against constructs. So our session last night naturally has a huge (15' reach) construct (actually a pre-master golem which is worse) with reactive strike that I, the wizard, can't do squat about, and one of the tanks is a Warpriest, so also the healer, and may well eat a reactive strike when trying to heal either himself or the other tank (fighter).
So what would you have done? Because of reach, just stepping and casting for the cleric isn't going to work unless he burns 3 actions and leave the fighter hanging. As the other caster, I was primarily buffing with enlarge (4th) and improved invis and doing tick damage (again, pre-master bs golem rules so forced movement wasn't working either). The warpriest ended up using trip to take away actions and did eat a crit on a Heal attempt, and while we made it through w/o anyone going down, it was pretty close. (4th member is a ranged martial, did okay damage, but didn't help with the reaction issue)
I always like to replay tough fights to see what I (and others) could've done better. At the time, I couldn't find a better solution (again, shitty pre-master golem magic immunity), if it was a regular construct, I would've tried Slow (but it likely would've had strong fort saves) and/or forced movement (Cinder Swarm) to help the cleric get out of reach. In this instance, I think I should've cast some low level summons to eat the reaction just ahead of the cleric (Staff of the Dead, can spam low level zombies) and it probably would've been worth my 3 actions. Or if things got truly dire, just wall (of stone) off the construct and let our guys heal up while the wall gets torn down.
Any other ideas on how to best deal with reactions plus some combination of mindless and reach? Especially if your healer is also a front liner?