Follow up: How testing is too much?
Hypothetical (because I love hypotheticals):
The Foundation has discovered an SCP that, whenever it eats someone, it pukes up a mystery fluid. The fluid is different each time, and it only eats humans. It is, however, otherwise safe as far as anyone can tell; no containment seems to be necessary beyond locking it in a room is required. Feeding it people does not appear to be neccesary to keep it alive.
Say after feeding it five D-class, no trend emerges as to the nature of the fluid and the SCP remains otherwise passive. However, while the liquid appears mundane, it sometimes contains chemicals not physically present in the room (one was a form of liquid titanium, for example). Do you stop testing here?
Say you kept going. After 20 D-class, the liquid seems to be connected to the personality and appearance of the D-class; the more angry they were, the more flammable it is. The more muscular they were, the more viscous the fluid. You still haven't identified the source of the liquid. Do you stop testing here?
Say you kept going. After 50 D-class, no new evidence is presented, but there is an anomaly: one D-class, who upon investigation turned out to be be only 16 years old, was not eaten by the SCP. Instead, she was simply ignored. A doctor proposes examining the effects of age by testing it on another 16 year old. Would you be okay with that?
Say that one is ignored to. Now they want to go younger, say a 12 year old. How about now, keep going?
The 12 year old gets eaten. They want to test a variety of ages, from 12 to 18, to see if a pattern emerges. Keep going?
I could continue, but you get the idea. I'm genuinely curious where you feel the line is. There is of course no wrong answer here, I just like seeing where others stand.