If anyone wants a related rabbit hole to go down, I actually came across
this thesis specifically regarding the subject of "first generation Canadian Punjabi Sikh parents’ beliefs about suicide and suicide-related behaviours."
Independent of suicide, I understand cremation to have importance in Sikh, Hindu, and related Indian cultures. It is believed to facilitate reincarnation and can be associated with purification. In this case, I imagine that the oven could have been used in a misguided attempt at cremation more so than a means of death.