@Kaarme
Not at all, it is just that reading the Index novel is obligatory to understand the true nature of his power. In the end, Railgun still is a spin-off of Index
Truth be told, if Othinus' "trials" say anything, there are billions of ways and more to kill Touma. His power is hard to use even if you count on the reluctant power hidden behind his Imagine Breaker.
Seeing Imouto's face just as shocked as Accelerator's when the scientists asked to kill her.. It just makes them normalizing their death so much more tragic....... all because the scientists brainwashed them (and Accelerator.. look how lost he is that all he's been told is being rebutted)