I have some doubts about the hypothetical, speculation only theory of an accidental bathtub drowning. I did a little research and found that the numbers are pretty low, especially for children older than 15 months.
Different reports from different years cite different numbers but overall those numbers are low compared to drownings in swimming pools, spas or lakes and rivers. (And for now I'm eliminating that Malik walked ~ 4 miles undetected to the Little Red River).
Given Malik's age of approximately two and a half years I question the likelihood that he drowned in the bathtub. Hypothetically speaking, in Malik's case we'd be looking at a scenario where he slipped under the water and stayed there long enough to drown without any attempt to pull himself up. The only way I can see that happening is if he fell and hit his head hard enough to daze or knock him out.
Anyway, here's one report on unintentional bathtub incidents covering a 5-year period. There were 434 fatalities. Here's a breakdown by age:
http://www.cpsc.gov/en/Newsroom/New...400-deaths-estimated-over-a-five-year-period/
All speculation and MOO.