You can't compare RDSA to PTK.

Share price can rise for a variety of reasons, but usually it is more buyers than sellers.

(More) Volume is always healthy, no matter how you cut it, price up or price down.

If you see a stock that’s appreciating on high volume, it's more likely to be a sustainable move. If you see a stock that’s appreciating on low volume, it could be a dead cat bounce. Logically, when more money is moving a stock price, it means there is more demand for that stock. If a small amount of money is moving the stock price, the odds of that move being sustainable are lower. Also, be careful of low-volume (or illiquid) stocks, where you could end up trapped in a pump and dump scheme. Even if you were trying to play the artificial move, you might not be able to find a seller if the volume is low and you'd be locked into a losing trade.

https://www.investopedia.com/articles/investing/060315/stocks-trade-volume-important.asp